Rock excavating machine



y 1960 s. L. STEWART u, ET AL 2,935,801

ROCK EXCAVATING MACHINE 3 Sheets-Sheet 1 Filed June 21, 1956 INVENTORS' SELDEN L. STEWART, n

MATHEW BERNARD WALDIN y 0, 1960 STEWART u, ET AL 2,935,801

ROCK EXCAVATING MACHINE Filed June 21, 1956 3 Sheets-Sheet 2 INVENTORS SELDEN L. STEWART, II

MATHEW BERNARD WALDIN MQW W ATTORNEYS y 1960 s. L. STEWART u, ET AL 2,935,801

ROCK EXCAVATING MACHINE Filed June 21, 1956 3 Sheets-Sheet 3 INVENTORS SELDEN L. STEWART,JI

MATHEW BERNARD WALDIN M )Mwuu ATTORNEYS ROCK EXCAVATING MACHINE Selden L. Stewart H, Coral Gables, and Mathew Bernard Waldin, Naranja, Fla.

Application June 21, 1956, Serial No. 592,805

Claims. (Cl. 37-86) This invention relates to excavating machines and more particularly to an excavating machine of the type embodying an endless digging conveyor operable to excavate a trench or the like.

Conventional trench digging machines have their end less digging conveyors mounted on the central portion United States Patent O rear of the traction vehicle and, hence, the width of the equal forces to the vehicle so that steering and other ma-' ni'pulations thereof are rendered diflicult, if not impractical.

Accordingly, it is an object of the present invention to provide an excavating machine ofthe type described in which the endless digging conveyor is mounted in lateral offset relation with the propelling vehicle, which conveyor embodies tooth means on the buckets thereof having.

a sutficient angle of approach withrespect to the material being dug to substantially tend to cause the conveyor during its own movement to move in the direction of travel and an area of contact in a plane parallel to the direction of travel to resist such movement beyond its power provisions to thereby offset the unequal forces transmitted to the vehicle and permit easy manipulation thereof.

The excavating machine of the present invention is particularly adapted for use in digging rock, such as limestone, shale, coral rock and the like, which are recovered in a substantially loose condition. The conventional trench digging machines operable to remove earth from ajLtrench for the purpose of laying pipe or the like embody buckets which must be mechanically cleaned during their travel in order to function properly. However, in dealing with loose granular material, the unloading of the same from the buckets can be accomplished solely Accordingly, it is another object of the present invention to provide an improved endless digging conveyor of the type described having a series of longitudinally spaced bucket assemblies thereon, which assemblies in' Patented May 10,1960

ments will be moved apart so as to permit dumping of the load.

Still another object of the present invention is the provision of a bucket assembly of the type described having improved tooth means embodied thereon, which tooth means has a substantial angle of approach to the material being dug and a sufficient area of contact in the direction of travel to prevent excessive digging-in of the teeth.

These and other objects of the invention will become more apparent during the course of the following detailed description and appended claims.

The invention may best be understood with reference to the accompanying drawings wherein an illustrative embodiment is shown.

'In the drawings:

Figure 1 is a side elevational view of an excavating machine embodying the principles of the present invention;

Figure 2 is an enlarged fragmentary view of the endless diggging conveyor showing the manner in which the buckets are opened and closed;

Figure 3 is a fragmentary front elevational view showing the manner in which the buckets are mounted on the chain of the conveyor;

Figure 4 is an enlarged detailed side elevational view :15; ofa bucket tooth; and

tractors, trucks or the like.

Figure 5 is an elevational view taken along line 5-5 of Figure 4.

Referring now more particularly to the drawings, there is shown in Figure 1 an excavating machine embodying the principles of the present invention. The machine includes a self-propelled vehicle, generally indicated at 10, which preferably is of conventional crawler tractor design. It will be understood that any type of propelling vehicle may be employed, such as conventional farm The vehicle 10 illustrated in the drawings, is provided with traction means in the form of laterally spaced track-laying assemblies 12 which are operable to propel the vehicle in the desired direction in the well-known manner.

The present invention is more particularly concerned with a novel endless digging conveyor, generally indicated at 14, which is arranged to be mounted on the vehicle 10. V The latter is of conventional construction and 0 forms no part of the present invention except insofar as it is combined with the conveyor to form an operative combination. The conveyor 14 may be mounted on the vehicle by any suitable means so .as to be disposed in a position laterally offset with respect to the traction means 12; As shown, this means may comprise a Ushaped yoke 16 having its bight portion disposed at the rear of the vehicle and the free ends of its legs pivoted to the central portion of the vehicle, as at 18. The yoke 16 may be moved about'the pivots 18 by means of hydraulic cylinders (not shown) or other suitable adjusting de-' operative digging. relation are closed so asto dig and convey loose granular material and are operative through: a curved portion of their endless path to move apart and effect a dumping of the material to a discharge station.

I Another object of the present invention is the pro-' vision of a novel material-digging and carrying assembly foran endless conveyor of the type' described which embodies separate elements arranged to be mounted on anendless chain so that during a substantially straight operative run thereof the members will be disposed, in rigid;

engagement defining a closed bucket and during the movenient of the chain around a mounting sprocket the ele- The conveyor 14 includes a main frame 20 which is rigidly secured to the yoke 16 in any suitable manner, such as by welding or'the like. Thus, the conveyor is mounted on the vehicle for vertical adjustment about the pivots 18 as an axisso that the depth ofthe out which the conveyor makes can be adjusted as is well known in the Mounted on opposite ends of the main conveyor frame 2i). is a pair of sprocket wheels 22 and 24. As shown,

' best shown in Figure 3 includes a pluralityof interconnected links 32, each of which is made up of a pair of laterally spaced arms 34. The.arms.are hentsothatthe lateral spacing between thesame at one end is greater than at the other. A pin 36 extends through adjacent ends of'the arms ofeach link and .throughza sleeve 38 so as to effect interconnection of the links. Inthe iconveutional-manner, suitable idler rollers 40maypbe'journaledon thelmain frame 20 for the purpose of stabilizing the links throughout their endless path of travel.

Mounted on the chain 30 is a series of longitudinally spaced material-digging and carrying assemblies, generally indicated at 42. Each assembly 42 comprises a tubular bucket member 44 which may be hexagonal in cross-section, although it will be understood'that other configurations may be employed, if desired. As shown, the tubular bucket member 44 includes a leading open end 46 and a-trailing open end .48 of smaller dimensions than the end 46 so as to form an inwardtaper in the member 44 from its leading end to its trailing end. As best shown in Figure 2, the tubular bucket member also includes a flat inner wall 50,-which, adjacent the leading open end 46, is rigidly secured to a chain link 32 by any suitable means, such as bolts or the like. The trailing end-of the wall 50 terminates short of the trailing open end of the tubular member, as as 51, as can be clearly seen from Figure 2.

Cooperating with the tubular buck member 44 .is a closure means, generally indicated at 52, which together with the tubular member in operative position defines a closed bucket operable during its movement to move apart to permit dumping of the load carried thereby. Each closuremeans 52 includes an inner wallplate 54, which, in the operative digging position of the assembly 42, is disposed in substantial alignment with the inner wall '50 of the bucket member 44. The .plate 54 has'its trailing end rigidly secured to a link 32 of the chain-by any suitable means, such as bolts or the like. Extending outwardlyfrom the plate 54'is a trailing'end closure plate 56. Theplate 56 is disposed at an obtuse angle with respect to the direction of travelin operative position and is :adapted to engage the open trailing end of. the bucket member so as to close the same. In order to add strength to the-plate56, a pairof triangular rib plates 58 maybe rigidly secured between the trailing surface thereof and the outwmd surface of the platex54.

Asbest shown in Figures 4 and 5, the leading end 46 of .each bucket member has suitably secured thereto a plurality of outwardly and forwardly extending :digging teeth, generally indicated at 60. Each tooth comprises a rigid body 62'having a substantially flat material-separating .surface 64 which is disposed at an angle with respect to the direction 'of travel thereof between 45 and 50.

This angle'constitutes the angle of approach of each tooth.

The rigid body 62 also includes a material-contacting surface 66 which is disposed substantially parallel with the direction of travel and forms with the surface 64 anrangle of between 40 and 45. As best shown in Figure "5, the tooth body '62 also includes a rib portion 68 which is disposed on the outward trailing portion thereof. This rib portion has an outer surface whichforms acontinuation of the material-contacting surface 66. In this manner, the entire surface 66 is of substantial transverse and longitudinal dimensions, withthe length thereof, measured'in the direction of travel, includingthe portion provided by the rib 68, being substantially equal'to the'width thereof. However, it will be noted that the area of'the contact surface 66 is substantially less than'the product of the transverse and longitudinal dimensions thereof. The "tooth body 62 has its 'outer end portion, including the ribs 68, formed so as to present a substantially uniform cross-sectional configuration along a plane parallel with the surface 66, asindicated at 70. If 'desired,'the

outer end of the material-separating surface 64 may be provided with an insert of a hardened material of any well-known type, 'as indicated at 72.

4 Operation 'As'was briefly noted above, the conveyor "14 of the present invention is particularly adapted for digging loose granular material such as might be employed in the construction of road beds or the like. Thus, in digging such material it is more important to be able to remove the same from a large area rather than to excavate a trench therein. Hence, the conveyor 14 is mounted in laterally offset relation to the propelling vehicle 10 so that the same can make successive transversals through the material and at all times contact a level support for the traction means 12 of the vehicle. This operation obviously cannot be obtained with conventional trench digging machines in which theconveyor is mounted in a position on the vehicle between the traction means thereof. That is, in this case, material cannot be removed over a large area because in subsequent transversals of the area, at least one of the track-laying assemblies of the vehicle must enter within a trench previously dug. Accordingly, it can be seen that due to the position of the present conveyor with respect to the vehicle, all of the material in a large area can be removed by the operation ofthe present machine.

'W-hile the lateral offset positon of the conveyor with respect to the vehicle is not in itself new, operation of machines of this type heretofore proposed have not been practical due to the unequal forces transmitted by-the conveyor to the vehicle. The machine of the present invention overcomes this problem by providing the material-digging and carrying assemblies 42 of the conveyor with tooth means which is operable during the movement of the conveyor itself to substantially tend to move the conveyor in the direction of travel. The conveyor teeth of conventional trench-digging machines have a relatively sharp, angle of approach of the order of 30 with respect to the direction of travel. The material-separating surface 64 of the present teeth are disposed at an angle of between 45 and 50 with respect to the direction of travel so as to provide a relatively large angle of approach. Thus, as the teeth move through the substantially straight operative run along their endless path, the material-separating surfaces 64 tend to move the assemblies and, hence, the entire conveyor into engagement with the material being dug or in the direction of travel. In other words, the large angle of approach causes the teeth to dig into the material and pull the conveyor therewith. Of course, such a large angle of approach may cause the assemblies to dig-in to an extent such that the power for moving the-conveyor will be insulficient and the same will stall. To offset this possibility, the teeth are provided with material-contacting surfaces 66 which are disposed parallel to the direction of travel and, hence, resist the digging-in of the teeth. .However, it will be noted that the entire contacting area of the surface is substantially less than the product of the transverse and longitudinal dimensions thereof. In this manner, there is .a substantial contact length in the direction of travel so as to resist excessive digging-in movement of the teeth, but

' the contact area is minimized so as to reduce friction.

Thus, it can be seen that the disposition of the teeth is sudh as to substantially tend to move the entire conveyor inthe direction of travel during the movement of the conveyor or stated differently, the operation of the conveyor itself is self-feeding. This action of the conveyor .in tending to move itself in the direction of travel by its own operation offsets the unequal forces transmitted thereby to the vehicle as a result of its position with respect thereto and enables the vehicle to be easily handled.

Referring now more particularly to Figure 2, the manner in'which-the assemblies 42 operate to dig, carry and dump the material will now be described. It will be noted that the endless path which the assemblies traverse is an elongated oval 'Withthe upper sprocket wheel 22 defining aesasoi a curved upper end and the lower sprocket wheel defining a curved lower end. Between these curved ends are substantially straight runs. The leading substantially straight run constitutes the operative digging run of the endless path and it will be noted that the chain links 32 during this run are in substantial longitudinal alignment. rrespondingly, the bucket member 44 and closure means 52 of each assembly define a closed bucket. That is, the closure plate 56 of the closure means is disposed in interengagement with the open trailing end 48 of its associated bucket, member. Preferably, "the links with which these members are 'rigid are spaced apart and, as shown, a single linkpis interposed therebetween. Thus, due to the engagement between the bucket members and the closure plates,"inward deflect-ion of the adjacent links is efie'ctively prevented. In other words, the three links disposed adjacent the assembly are made rigid by the interengagement of the assembly parts and the entire chain is efiectively stabilized during theoperative run. After the assembly moves around the lowersprocket wheel 24the parts thereof will assume their closed'buck'et deposition" and as the same begin-their movement upwardly, the teeth 60 thereof. will dig into the material and the materialloosened will be caught in the closed bucket.

The material thus dug is carried upwardly until the link rigid with the bucket member begins to travel around the upper sprocket wheel 22. It will be seen that as this link moves around the sprocket wheel, the same will be moved into an angular position with respect to the link rigid with the closure means and thus, the bucket member will be moved into an angular position with respect to the closure plate 56. This position of one of the assemblies is clearly illustrated in the upper left hand corner of Figure 2. As the two elements of each assembly move apart, in the manner indicated above, the material carried thereby is permitted to flow out of the open trailing end of the bucket member and directed by the closure plate 56 to a dumping station. As shown in Figure 1, an angle plate 74 is disposed at the dumping station to direct the material forwardly. It will be understood that suitable conveying means may be provided on the vehicle to convey the material received on the plate 74 to a desirable dumping location or to a suitable transporting vehicle. The inner plate 54 of the closure means also serves to rigidify the chain links during their operative digging run and when the assembly moves around the upper sprocket this plate has the effect of initiating the discharge of the material since it moves inwardly of the bucket member Within which the material is disposed. As shown in Figure 2, after the assembly has moved around the upper sprocket 2.2 and begins down the trailing run the elements of the assembly will again move into interengaged position. Normally, however, this run is not utilized to perform any digging action so that the assembly will merely move along this run until the lower sprocket wheel 24 is reached. Of course, as they are moved around this sprocket, they will open but as they begin the upper movement along the operative run they are closed in the manner previously described.

It can thus be seen that there has been provided an excavating machine in which a digging conveyor is mounted in offset relation iwth respect to the traction means of a self-propelling vehicle. The self-feeding operation of the conveyor itself is such as to offset the unequal forces transmitted to the vehicle by reason of its position with respect thereto so that the vehicle may be easily handled and maintained in a straight path of movement.

The material-digging and carrying assemblies of the conveyor are operable to move from a normally closed digging position into an open position solely due to their movement through a curved portion of its endless path. The elements of the assembly are rigid with the conveyor chain and, hence, in their operative digging position serve to rigidify the same and thus stabilize the entire operation. Furthermore, dumping is efiectively securedwithout the necessity of providing movable parts within the assembly itself which must be engaged by cams or the like in the manner heretofore proposed. The present construction is thus simple in operation and requires no moving parts other than the chain itself.

It thus will be seenvthat the objects of this invention have been fully and effectively accomplished; It will be realized, however, that the foregoing specific embodiment has been shown and described only for the purpose of illustrating the principles of this invention and is subject to extensive change without departure from such principles. Therefore, invention includes all modifications encompassed within the spirit and scope of the following claims.

We claim; V

1. In an endless digging conveyor of the type described, upper and lower sprocket wheels, an endless series of interconnected links trained about said sprocket wheels, a plurality of longitudinally spaced material-digging and carrying assemblies carried by said links for movement therewith along an endless path having a' substantially straight digging runin which the assemblies move upwardly from said lower sprocket wheel to said upper sprocket wheel, each of said assemblies comprising leading and trailing cooperating members carried by said links so as to be moved into a closed interengaging position defining a bucket having an open leading end and a closed trailing end in response to the movement of said certain links through said digging run and to move into an open separated position in response to the movement of said certain links around said upper sprocket wheel so as to permit dumping of the material carried by the bucket outwardly through the trailing end thereof, said leading member including a tubular body rigid with one of said links and having an open leading end and an open trailing end, said trailing member including a plate rigid with a link spaced from said one link and extending outwardly from said path of travel so as to close said open trailing end during said digging run.

2. An endless conveyor as defined in claim 1 wherein the open leading end of said tubular body has provided thereon tooth means comprising a plurality of digging teeth each of which includes a leading edge of substantial width, an outer surface extending rearwardly of said leading edge parallel with said endless path during said digging run, said outer surface having a longitudinal dimension in the direction of movement substantially equal to the width of said leading edge, the area of said outer surface being substantially less than the product of its transverse and longitudinal dimensions, a leading surface extending rearwardly from said leading edge and defining with said outer surface an angle of between 40 and 45, the outer portion of each tooth measured in the direction of said outer surface having a substantially uniform crosssectional configuration in a plane parallel to said outer surface which conforms in shape to the shape of the latter.

3. An endless conveyor as defined in claim 2 wherein said outer surface is T-shaped.

4. An endless conveyor as defined in claim 1 including, in combination, a self-propelled vehicle having laterally spaced traction means and means for mounting said conveyor on said vehicle in laterally ofiset relation to said remote traction means a distance greater than the lateral spacing between said pair of traction means, ooth means on the leading end of each ofsaid buckets, said tooth means for each bucket comprising spaced teeth each having a point portion extending forwardly and outwardly from the leading end of the associated bucket, thepoint portion of each tooth having a-leading surface disposed at an angle of the order of 50 with respect to the digging run of the path of movement of said buckets and an outer surface extending rearwardly from the outer edge of said leading surface in parallel relation to the digging run of the path'of said movement, the outer surface of each tooth point portion having transverse and longitudinal dimensions substantially equal to thewidth of said leading surface at its outer edge and an area substantially less than the product of said transverse and longitudinal dimensions defining a rectangle having spaced portionsremoved from the :lower corners thereof, the disposition of thetleading surface of said teeth during said digging run being such as to tendto move theentire conveyor in the direction of movement of the vehicle asia result of the movements .of the buckets thereof, the disposition-and area of the outer surface of said teeth during said digging run being such as to resist such movement beyond the powerlimitation of the conveyor whereby the operation of the conveyor tending to propel itself in. the direction-of travel of the vehicle substantially offsets the unequal forces transmitted to the vehicle as a result of the laterally offset position of 'the conveyor and permits easy handling of the machine.

7 References Cited in the file of this patent UNITED STATES PATENTS Re. 16,997 Barber June'19,1928 1,131,071 Monahan ....'Mar. 9, 1915 1,703,320 Penote Feb. 26, 1929 1,764,949 George June 17,1930 1,769,074 Ruatti "July 1,1930 2,339,128 Younie Jan. 11,1944 2,686,981 Vaughn Aug. 24, 1954 FOREIGN PATENTS 977,583 France v Nov. 15, 1950 159,867 Germany Apr. 7, 1905 103,025 GreatBritain' Ian..11, 1917 428,327 Great Britain May 10, 1935 685,330 Great Britain "Dec. 31, 1952 

